This is a very easy table runner which is the width of your fabric when done. Thank you, Sally, for the suggestion.
Take 12″ of your focus fabric and 18″ of the bottom fabric, width of fabric. Place right sides together and sew each of the long edges. No, they won’t match, because you want the bottom one to fold over to the top.
After sewing, you have a tube to turn right side out. (I pressed the seams to the center before turning). Then press so the borders are the same width.
Fold the end together toward the bottom side. Can you see my line of stitching (near the top of photo) where I sewed the end closed. Repeat on other end.
When opened, it looks like this. I pressed the seam you see before turning it to the inside.